The square head increases the club head's Moment of Inertia (MOI) or resistance to twisting during off-center hits

A wider, taller sweet spot for consistently longer drives

Moving the center of gravity farther back makes the clubface easier to square for straighter drives

You will find the new I Drive Square very hard not to hit long and straight. USGA has a new limit on MOI for this exact reason.(moment of inertia relates to stability on off-center-hits. A key to maximizing moment of inertia is to push weight as far away from the center of gravity as possible.)